The invention relates to a terminal for the electrical connection of a plurality of electrochemical cells of an accumulator, comprising a U-shaped outer rail and an actuating element.
Today, electrical and electronic devices which may be operated independently of a power supply are increasingly being used. Powerful devices and the desire for a long operating time demand efficient accumulators. Of course, these should be compact and light but nevertheless have a high energy content. In particular, these requirements are applicable for electric vehicles. Battery- and accumulator-operated electric vehicles are no longer inconceivable today. While their existence had long been limited to niche applications, for example as fork-lift trucks and mine cars, the introduction of electric vehicles into road traffic in large numbers is now imminent.
A substantial point in the construction of accumulators is the interconnection of individual cells, since the required voltages (e.g. 400 volt and higher) and the required energy contents (e.g. 100 Ah and higher) cannot otherwise be achieved. Owing to the high currents, large conductor cross-sections are additionally required for the connection of the cells. The prior art discloses some solutions for this purpose.
US 2004/0102096 A1 discloses for this purpose, for example, an apparatus for connecting a plurality of prismatic cells, in which the connection lugs of the cells are inserted from below through an electrically insulating plate having suitable cut-outs. A counter-plate having metallic pins which fit into said cut-outs is pushed in from above. The cut-outs have a wedge-shape profile so that the connection lugs of the cells are contacted when the pins are pressed in.
DE 10134143A1 furthermore shows a rail-like cell connector having a U-profile. The connection lugs of the cells are soldered or welded to in each case one limb of the U-profile, so that series or parallel connection of the cells results.
Finally, DE 10 2004 001 876 B3 moreover discloses an arrangement of prismatic cells whose connection lugs are bent into a Z-shape so that the lugs of all cells rest flat against one another. With the aid of a (screw) terminal, the connection lugs are connected to one another.
Unfortunately, the known apparatuses have disadvantages. For example, the apparatus disclosed in US 2004/0102096 A1 is not very flexible because a separate terminal plate has to be produced for each type of connection. Moreover, in certain circumstances, manufacturing tolerances result in individual cells making only poor contact. The resulting high contact resistance in combination with very high currents (250 amps or more in the automotive sector) can lead to dangerous heating of the contact point and to damage thereof or even destruction. If the relevant contact point is touched with ignitable materials, this can moreover lead to a fire.
In the case of the solution disclosed in DE 101 34 143 A1, the cells are irreversibly connected. Repair or replacement of the cells is therefore not possible or is possible only with very great difficulty. Moreover, the soldering or welding of the cell vanes can lead to damage or even destruction of the cell during the production of the accumulator if, for example, the heat input “migrates” into the cell.
Finally, in the connection method presented in DE 10 2004 001 876 B3, connection lugs of different length are provided and are bent differently. This solution is therefore very inflexible.